1. Field of the Invention
This invention relates to a device for laying and attaching a resistance wire to a thermoplastic support film for the production of a laminated glazing that can be heated electrically, including a heated pressure roller which rolls over the support film to bond the resistance wire to the film, a support for a wire bobbin, and a wire guide device.
2. Discussion of the Background
In the case of a known device of this type which is used for laying antenna wire on the interposed plastic layer of a windshield of laminated glass, the wire is applied in a straight line on the support film (document DE-AS 20 43 706). This known device is not suitable for applying an electric resistance wire in an undulating shape on the support film.
In a known device for the application of a resistance wire in an undulating shape, the wire is brought above the support film by a laying device having the shape of a guide shoe driven with a periodic crosswise movement and the wire is at the same time embedded in the film (document DE-AS 16 79 930). The undulating shape of the wire is in this case produced directly on the surface of the film and the wire, at the moment it is laid, must be attached sufficiently to keep it from coming loose immediately under the effect of the tension created by the laying device. For this reason, the speed of laying the wire is subject to narrow limits.
In other devices known for laying a resistance wire in an undulating shape, ring gears placed obliquely relative to one another roll over the film, receive the wire between their teeth which draw near one another and deform the wire in an undulating manner immediately before it is laid on the support film, then embed it in the support film either themselves or with a pressure wheel provided with pressing pins meshing between the teeth (document DE-AS 22 04 939). These devices certainly make possible a high speed of laying, but they require frequent maintenance, because particles of the thermoplastic support film adhere easily to the teeth and to the pressing pins engaging in the surface of the support film and unfavorably affect the operating ability of the device.